An environmentally-friendly floating raft mussel culture farm has been expanded in Saldanha Bay using high-density polyethylene (HDPE) pipes.

The Cape Agency for Sustainable Integrated Development in Rural Areas (CASIDRA), which is a project implementation agent for the Department of Agriculture, contracted DPI Trading to supply R1,2-million worth of 800 mm HDPE pipes to the black empowered Imbaza mussel farm project.

The pipes are being used to form the base for flotation rafts that are used to culture the mussels, and CASIDRA project co-ordinator Clovis Bhiya reveals that the HDPE material serves as a far more robust alternative to industry standard wooden beams.

HDPE pipe is highly durable, and  its UV-resistant properties ensure that prolonged exposure to the sun will not result in brittleness and cracking,” he explains.

Bhiya adds that mussel culture on floating rafts provides the advantage of growing a large amount of mussels in a small area, thereby reducing competition with other uses of coastal resources, while ensuring that the mussels are protected from predation by seagulls by using nets. “The HDPE rafts also create favourable hydrodynamics for mussel feeding.”

According to Bhiya, mussel raft culture is environmentally sustainable, as the mussels feed on natural phytoplankton in monitored and approved shellfish growing areas. “The rafts and mussel cultures act as artificial reefs that attract dozens of species of invertebrates, fish and birds too.”

DPI Trading Western Cape external sales representative Charlene Curlewis points out that a total of 384 m of pipe, produced by leading Southern African extruded pipe manufacturer Sangio, was supplied to the Imbaza project in 12 m lengths to form the base of four new rafts. Sangio recently invested in the large bore extruder used to manufacture the pipe for this project, and is now capable of manufacturing HDPE pipe in diameters ranging from 16 mm to 1000 mm.